Electromagnetic device having a resilient shading coil



Nov. 1, 1966 H. A. RIDER. JR 3,283,275

ELECTROMAGNETIC DEVICE HAVING A RESILIENT SHADING COIL Filed May 15, 1.964 2 Sheets-Sheet 1 INVENTOR #77 Henry A. Ridendr. Fig.9. BY j LUMJ ATTORNEY Nov. 1, 1966 H. A. RIDER. JR 3,283,275

ELECTROMAGNETIC DEVICE HAVING A RESILIENT SHADING COIL Filed May 15, 1964 2 Sheets-Sheet 2 United States Patent M 3,zs3,27s ELECTROMAGNE'HC DEVICE HAVlNG A RESELIENT HADHNG COIL Henry A. Rider, .lr., Westminster, Calif., assignor to Westinghouse Electric Corporation, Pittsburgh, Pa, a corporation of Pennsylvania Filed May 15, 1964, Ser. No. 367,784 Claims. (Cl. 335-245) This invention relates generally to electromagnetic devices and more particularly to electro-magnets with shaded pole faces.

Electromagnetic devices such, for example, as relays which are built for alternating .current operation, are generally provided with shading coils to mitigate the force pulsations between the armature and the core member to thereby prevent undue chattering. The trend in modern industry is toward quiet operation and in many installations, noise is not tolerated. Thus, in many applications, if the shading coil fails due to breakage or because it becomes loose and falls from the magnet, the magnet is no longer fit for the particular application and the magnet is discarded. Thus, it is important to provide effective and dependable means for securing a shading coil to a magnet member. The means for attaching the shading coil should also be adaptable to a production line assembly process.

Accordingly, an object of this invention is to provide an improved shaded-pole electromagne't with improved means securing a shading coil to one of the magnet members.

Another object of this invention is to provide an proved shaded-pole electromagnet with a magnet member and shading coil constructed such that the shading coil is readily assembled to the magnet member and, when assembled, is effectively secured in position.

A further object of this invention is to provide an ill)- proved, dependable and efficiently-assembled shaded-pole electromagnetic device.

The invention, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description when read in conjunction with. the accompanying drawings.

In said drawings:

FIGURE 1 is a sectional view of an electromagnetic control device constructed in accordance with principles of this invention and taken generally along the line II of FIG. 2;

FIG. 2 is a sectional view taken line IlII of FIG. 1;

FIG. 3 is a plan View of part of the core member seen in FIGS. 1 and 2 and illustrating one pole face of the core member with a shading coil secured to the core member at the pole face;

FIGS. 4 and 5 are plan and side views res ectively of the shading coil seen in FIG. 3; I

BIG. 6 is a partial side view of one leg of the generally E-shaped core member seen in FIGS. 1 and 2 and illustrating the groove means disposed in the pole face of the core member for receiving the shading coil of FIGS. 4 and 5;

FIGS. 7, 8 and 9 are partial side views with the shading coil shown in section and illustrating three different positions of the coil during the assembly of the coil;

FIG. 10 is a partial View illustrating part of one leg of a modified form of core member for receiving the shading coil of FIGS. 39;

FIGS. 11 and 12 are plan and side views respectively of a modified form of shading coil;

generally along the 3,283,275 Patented Nov. 1, 1966 FIG. 13 is a partial side view of part of one of the legs of a modified core member;

FIGS. 14 and 15 are views similar to FIGS. 8 and 9 illustrating two positions of the coil of FIGS. 11 and 12 during the assembly of the coil to the core member of FIG. 13; and

FIG. 16 is a plan view similar to FIG. 3; but illustrating the core and coil member of FIGS. 11-l5.

Referring to the drawings, and particularly to- FIGS. 1 and 2, there is shown therein an electromagnetic control device 7, which is in this case a four-pole relay, constructed in accordance with the principles of this invention. The relay 7 is of the type that is described in more detail in the patent to Gust-ov Jake'l, Patent No. 3,088,058, issued April 30, 1963.

The relay 7 comprises a housing comprising a base 13 and a cover 15, both of molded insulating material. The housing parts 13 and 15 are firmly held together as a unit by means of suitable bolts (not shown). An E-shaped main magnet or core member 17 is supported, with its legs extending upwardly, in the housing base 13. An energizing conducting winding, or coil 19, that is disposed on a suitable spool 21 of insulating material, is positioned over the middle leg of the core member 17. An E-shaped armature 25 is provided to cooperate with the core member 17. The armature 25 is connected to an insulating contact carrier 27 by means of a pin 29 that pivotally mounts the armature 25 on the contact carrier 27 so that the armature is mounted for limited rotational movement in the plane of the paper as seen in FIG. 2. As can be seen in FIG. 1, each of the magnet members 17 and 25 comprises a plurality of laminations of a suitable low reluctance material such as soft iron. A separate shading coil 31 is secured to each of the two outer legs of the core member 17 at the pole face of each core member in a manner to be hereinafter specifically described.

The relay 7 is a four-pole relay. Each pole unit comprises two stationary contact structures 32, each of which has a solderless terminal connector 33 connected thereto at its outer end and a stationary contact 35 secured thereto at its inner end. In each pole unit, a bridging contact structure 39, having a contact 41 at each of its two opposite ends, is provided to bridge the stationary contacts 35. The bridging contact structure 39 is supported on the contact carrier 27 in an opening 43, and it is maintained in position by means of a spring 45 that not only positions the bridging contact structure 39; but also acts to permit some motion of the bridging contact structure 39 upon contact engagement to thereby provide that the contacts will mate properly when they are closed. The contacts 35, 41 are normally open contacts although they are shown in FIGS. 1 and 2 in the closed position. It is to be understood that the contacts can be made normally open or normally closed, in a manner well known in the art, depending upon the particular control requirements. Two springs 47 (only one of which is shown in FIG. 1) are provided to bias the contact carrier 27 away from the closed position seen in FIGS. 1 and 2 to thereby provide for an opening operation of the relay 7. As can be seen in FIG. 1, a similar contact structure is provided in each of the four stalls 49 of the relay 7. Each of the stalls 49 is formed by means of two opposite insulating barriers 51 that are molded integral with the housing cover 15.

The relay or contactor 7 is shown in the energized position in FIGS. 1 and 2. In this position, the coil 19 is energized by a suitable power source to attract the armature 25 to a position wherein the two outer legs of the armature 25 engage the pole faces 55 of the two outer legs of the core member 17 maintaining the contact carrier 27 in the lowermost position. The core 17 and armature 25 are constructed to form an air gap 52 between the center legs thereof in the energized position. When the contact carrier 27 is in the lowermost position seen in FIGS. 1 and 2, each of the four bridging contact members 39 closes a circuit between the associated stationary contacts 35. Upon deenergization of the coil 19,. the armature 25 and contact carrier 27 will be moved upward by means of the springs 47 to thereby simultaneously move the four bridging contact members 39 upward to an open-circuit position. As was previously described, the stationary contacts 35 and bridging contacts 41 can be readily adapted to provide for normally closed contacts rather than normally open contacts in a manner well known in the art.

Improved means are provided for securing the shading coils 31 to the outer legs of the magnetic core member 17 There is shown, in FIG. 6, part of one leg (the right-hand leg as seen in FIG. 2) of the core member 17. Two grooves 61 and 63 are formed in the pole face 55 of the core member. As can be seen in FIG. 3, the grooves extend transversely across the pole face 55. There is shown, in FIGS. 4 and 5, the generally rectangular shaped shading coil 31 having two end legs 65, a side leg 67 and another side leg 69. The shading coil 31 comprises a member of conducting material having good spring characteristics or resiliency. Copper, brass or silver are examples of good basic conducting materials and, when any one of these materials is alloyed in order to provide the desirable resiliency, the alloyed material can be utilized as the material forming the shading coils of this invention. For example, the shading coil can be formed from a beryllium copper alloy, at Zirconium copper alloy or a cadmium copper alloy. A specific example of a suitable shading coil is a shading coil formed from a beryllium copper alloy having the composition of about 98% copper, 1.9% beryllium and 0.2% nickel. The shading coil may be formed by any suitable method. The shading coil member may be stamped from sheet material, or it may be formed for example, by slicing off coil members from an elongated tube of the desired material.

The means for securing the shading coil 31 to the core member 17 will be described with reference to FIGS. 79 and with reference to the dimensions that are designated in FIGS. 46. Referring to FIG. 7, the leg 69 of the coil 31 is first placed endwise into the groove 61. The thickness e (FIG. 5) of the leg 69 is less than the neck a (FIG. 6) of the groove 61 so that the leg 69 can be freely moved endwise down into the position seen in FIG. 7. The coil 31 is then rotated moving the leg 67 toward the groove 63 until the leg 67 rests on a slanted surface 71 adjacent the groove 63 (FIG. 8). As is seen in FIGS. 79, the surface 71 slants away from the groove 61 and toward the groove 63. The dimension b (FIG. 6) of the slot 61 is great enough to permit the rotation (FIGS. 79) of the leg 69 in the lower well-portion of the groove 61. When the coil 31 is in the position disclosed in FIG. 8, the leg 67 of the coil is then forced down the slanted surface 71 of the core 17 which action springs or flexes the coil 31 flexing the leg 67 to the right (FIG. 8) springcharging the generally resilient coil 31, and near the end of this movement, the spring-charged coil 31 discharges moving the leg 67 into the lower portion 73 of the groove 63 under a ledge 75. As can be seen in FIG. 4, the leg 67 of the coil 31 is bowed to enhance the flexing action of the coil during the mounting operation. The dimension b (FIG. 4) of the coil 31 is less than the dimension 0 (FIG. 6) of the core member 17 so that the coil will be mounted in a charged condition (FIG. 9) with the legs 69 and 67 being biased into engagement with the side walls of the grooves 61 and 63 respectively to thereby provide an interference fit to hold the coil 31 in the mounted position. Although the dimension d of the leg 69 is less than the dimension b of the groove 61 so that the leg 69 can assume the position of FIG. 9, the dimension d of the leg 69 is greater than dimension a of the groove 61 so that the leg 69 cannot be readily removed from the slot 61. The leg 67 is held in the lower portion '73 of the groove 63 under the ledge 75.

A modified form of core member is disclosed in FIG. 10. The core member 117 of FIG. 10 is the same as the core member 17 of FIG. 6 except that the part 77 (FIG. 6), which is the part of the core member that is to the right of the groove 63, is eliminated in the core member 117 of FIG. 10. The reference characters of FIG. 10 that designate parts that are the same as the parts of the first embodiment (FIGS. 19) are the same as those used in the first embodiment except that the reference characters of FIG. 10 are all preceded by the numeral 1. -Whereas the core member 17 (FIG. 6) comprises two grooves 61 and 63 both of which are bounded on both sides by parts of the pole face 55, the core memher 117 of FIG. 10 comprises only one groove 161 that is bounded on both sides by the pole face 155. The slanted surface 171, ledge 175 and groove 173 are provided at the pole face and at the right-hand (FIG. 10) end of the one leg of the core member 117. The shading coil 31 of FIGS. 4 and 5 is mounted on the core member FIG. 10 in the same manner as that hereinbefore described with respect to FIGS. 79.-

Another embodiment of the invention is disclosed in FIGS. 11-16. The reference characters of FIGS. ll-l6 that designate parts that are similar to the parts of the first embodiment (FIGS. l9) are the same as those used in the first embodiment except that the reference characters of FIGS. 11-16 all start with the numeral 2. Referring to FIGS. l1l6, the bowed leg 267 of the shading coil 231 is first placed into a slot or groove 261 formed in the side of the core member 217 in proximity to the pole face 255. The coil 231 is then rotated and moved to the left moving the leg 269 thereof toward the groove 263 in the pole face 255 until the leg 269 rests on the slanted surface 271 of the core member 217 (FIG. 14). Thereafter, the leg 269 is forced down spring-charging the coil 231 principally at the leg part 267 thereof, and when the leg 269 clears the ledge 275, the spring biased coil 2.31 will discharge moving the leg 269 into the mounted position under the ledge 275 (FIG. 15). The dimension b (FIG. 11) of the shading coil 231 is less than the dimension c (FIG. 13) of the core member 217 so that the resilient shading coil 231 will be spring charged in the mounted position disclosed in FIG. 15 in the same manner as was hereinbefore described with reference to the mounting of the coil 31.

It is to be understood that in the embodiment of FIGS. 1-9 the leg coil 67 could be mounted first in the slot 61 and thereafter the leg 69 could be forced against the surface 71 into the groove 73, and that in the embodirnent of FIGS. 11-16 the leg 269 could be mounted first 1n the groove 261 and thereafter the leg 267 could be forced against the surface 271 into the groove 273.

From the foregoing, it can be understood that there is provided by this invention an improved electromagnetic device comprising a novel shaded-pole electromagnet. The shading coil is secured in position without any time consuming mechanical deforming operation of the coil such as crimping, swedging, etc., which deforming operations can in some instances shorten the mechanical life of the coil. The shading coil is secured in position without any time consuming soldering or other bonding operation. There are no additional mounting pieces such as adjustable clamps used to mount the shading coil in positlon. The magnet member and shading coil of the improved shaded-pole electromagnet are constructed such that the shading coil is readily assembled to the magnet member and, when assembled, is effectively secured in position for reliable and long-lasting operation.

While the invention has been disclosed in accordance with the provisions-of the patent statutes, it is to be understood that various changes in the structural details and arrangement of parts thereof may be made without departing from some of the essential features of the invention.

It is desired, therefore, that the language of the appended claims be given as reasonably broad an interpretation as is permitted in view of the prior art.

I claim as my invention:

1. An electromagnet comprising two magnetic members, means operable to effect relative movement between said magnetic members to increase and decrease the distance between said members, one of said magnetic members comprising a pole face facing the other of said magnetic members, two spaced generally parallel grooves in said pole face of said one magnetic member, a shading coil comprising a generally resilient member of conducting material, said shading coil being in a supported position on said one magnetic member, each of said grooves being open to receive said shading coil, a first of said grooves forming a first ledge under said pole face and between the opening of said first groove and the opening of the second of said grooves, the second of said grooves forming a second ledge under said pole face and between the opening of said second groove and the opening of said first groove, said shading coil comprising two spaced leg portions, a first of said leg portions being disposed in said first groove generally under said first ledge, the second of said leg portions being disposed in said second groove generally under said second ledge, soid groovesbeing so formed that the dimension between said leg portions is greater when said coil is in the supported position than when said coil is in the unsupported position whereby said coil is maintained in said supported position in said grooves in a charged condition.

2. An electromagnet comprising two magnetic members, means supporting said magnetic members for relative movement, one of said magnetic members comprising a pole face facing the other of said magnetic members, said one magnetic member having a first groove means therein and a second groove means therein spaced from said first groove means, said first groove means comprising a first ledge under said pole face, said second groove means comprising a second ledge under said pole face, a shading coil comprising a generally resilient member of conducting material, said shading coil comprising a first leg and a second leg disposed opposite said first leg, said first leg being positioned in a first of said groove means generally under said first ledge, said second leg being positioned in the second of said groove means generally under said second ledge, said second groove means comprising a slanted surface slanted in a direction diverging away from said first groove means and a groove portion disposed generally under said slanted surface to form said second ledge, and said shading coil being supported with the resilience of said shading coil spring-biasing said first leg into position in said first groove means generally under said first ledge which resilience spring-biases said second leg into position in said groove portion generally under said second ledge such that said shading coil must be flexed to be removed from said one magnetic member.

3. An electromagnet comprising two magnetic members, means supporting said magnetic members for relative movement, one of said magnetic members having a first groove means therein and a second groove means therein spaced from said first groove means, a shading coil comprising a generally resilient member of conducting material, said shading coil comprising a first leg and a second leg disposed opposite said first leg, one of said legs being bowed, said second groove means comprising a slanted surface slanted in a direction diverging away from said first groove means and a groove portion disposed generally under said slanted surface, and said shading coil being disposed with said first leg being positioned in said first groove means and said second leg being positioned in said groove portion such that said shading coil must be flexed to be removed from said one magnetic member.

4. An electromagnetic device comprising two magnetic members and means supporting said magnetic members for relative movement, one of said magnetic members comprising a pole face disposed principally along a plane that is generally normal to the direction of said relative movement, said one magnetic member having a first elongated groove means therein extending transversely across said pole face and a second elongated groove means therein extending transversely across said pole face, said second elongated groove means being generally parallel to said first elongated groove means, one of said groove means comprising a generally slanted surface diverging away from said pole face and away from the other of said groove means and leading to a groove portion that is disposed under said slanted surface, a shading coil comprising a generally resilient annular member of conducting material, said shading coil comprising a first generally elongated leg and a second generally elongated leg disposed generally parallel to said first generally elongated leg, said shading coil being supported on said one magnet member with a first of said legs being disposed in said groove portion of said one groove means and the second of said legs being disposed in said other groove means, the dimension between said first and second legs of said shading coil when said shading coil is in the unsupported position being less than the dimension between said groove portion and the other of said groove means whereby said shading coil is supported on said one magnetic member with said first and second legs being flexed apart such that the resilience and shape of said shading coil along with the shape of said one magnetic member provide a spring-charged mounting construction.

'5. An electromagnetic device comprising two magnetic members and means supporting said magnetic members for relative movement, one of said magnetic members comprising a pole face disposed principally along a plane that is generally normal to the direction of said relative movement, said one magnetic member having a first elongated groove means therein extending transversely across said pole face and a second elongated groove means therein extending transversely across said pole face, said second elongated groove means being generally parallel to said first elongated groove means, one of said groove means comprising a generally slanted surface diverging away from said pole face and away from the other of said groove means and leading to a groove portion that is disposed under said slanted surface, a shading coil comprising a generally resilient member of conducting material, said shading coil comprising a first generally elongated leg and a second generally elongated leg disposed generally parallel to said first generally elongated leg with one of said legs being bowed toward the other of said legs to permit said legs to be more readily flexed apart, said shading coil being supported on said one magnet member with a first of said legs being disposed in said groove portion of said one groove means and the second of said legs being disposed in said other groove means, the smallest dimension between said first and second legs of said shading coil when said shading coil is in the unsupported position being less than the dimension between said groove portion and the other of said groove means whereby said shading coil is supported on said one magnetic member with said first and second legs being flexed apart such that the resilience of said shading coil operates to bias parts of said shading coil into frictional engagement with parts of said one magnet member.

References Cited by the Examiner UNITED STATES PATENTS 1,823,979 9/1931 Jordon 317184 X 2,157,844 5/1939 Armstrong et al 317-184 2,342,797 2/1944 Ellis et al 317184 BERNARD A, GILHEANY, Primary Examiner. G. HARRIS, JR., Assistant Examiner. 

1. AN ELECTROMAGNET COMPRISING TWO MAGNETIC MEMBERS, MEANS OPERABLE TO EFFECT RELATIVE MOVEMENT BETWEEN SAID MAGNETIC MEMBERS TO INCREASE AND DECREASE THE DISTANCE BETWEEN SAID MEMBERS, ONE OF SAID MAGNETIC MEMBERS COMPRISING A POLE FACE FACING THE OTHER OF SAID MAGNETIC MEMBERS, TWO SPACED GENERALLY PARALLEL GROOVES IN SAID POLE FACE OF SAID ONE MAGNETIC MEMBER, A SHADING COIL COMPRISING A GENERALLY RESILIENT MEMBER OF CONDUCTING MATERIAL, SAID SHADING COIL BEING IN A SUPPORTED POSITION ON SAID ONE MAGNETIC MEMBER, EACH OF SAID GROOVES BEING OPEN TO RECEIVE SAID SHADING COIL, A FIRST OF SAID GROOVES FORMING A FIRST LEDGE UNDER SAID POLE FACE AND BETWEEN THE OPENING OF SAID FIRST GROOVE AND THE OPENING OF THE SECOND OF SAID GROOVES, THE SECOND OF SAID GROOVES FORMING A SECOND LEDGE UNDER SAID POLE FACE AND BETWEEN THE OPENING OF SAID SECOND GROOVE AND THE OPENING OF SAID FIRST GROOVE, SAID SHADING COIL COMPRISING TWO SPACED LEG PORTIONS, A FIRST OF SAID LEG PORTIONS BEING DISPOSED IN SAID FIRST GROOVE GENERALLY UNDER SAID FIRST LEDGE, THE SECOND OF SAID LEG PORTIONS BEING DISPOSED IN SAID SECOND GROOVE GENERALLY UNDER SAID SECOND LEDGE, SAID GROOVES BEING SO FORMED THAT THE DIMENSION BETWEEN SAID LEG PORTIONS IS GREATER WHEN SAID COIL IS IN THE SUPPORTED POSITION THAN WHEN SAID COIL IS IN THE UNSUPPORTED POSITION WHEREBY SAID COIL IS MAINTAINED IN SAID SUPPORTED POSITION IN SAID GROOVES IN A CHARGED CONDITION. 